Information Recording Method and Information Recording Apparatus for Recording Medium

ABSTRACT

A recording method for recording data in basic reproduction unit to a recording medium having a first recording layer and a second recording layer, includes detecting a size of an unrecorded region of the first recording layer while recording data in the basic reproduction unit (ex. “Cell” unit) in the first recording layer, comparing the size of the unrecorded region of the first recording layer with a specified value (allowable maximum size of the basic reproduction unit, or size of data about to be recorded in the first recording layer), and stopping recording in the first recording layer at the boundary of the basic reproduction unit when the size of the unrecorded region is smaller than the specified value, and recording a subsequent data in the second recording layer.

TECHNICAL FIELD

The present invention relates to a recording method and a recordingapparatus for recording medium having two recording layers.

BACKGROUND ART

Hitherto, a DVD (digital versatile disc) is known as recording mediumfor recording video, audio, computer data, and other various contents.Depending on the application, various standards of DVD have beenspecified. One of them is DVD-Video standard (see pages VI 3-5 ofnon-patent document 1).

In the DVD-Video standard, a basic reproduction unit of AV data isdefined as a “Cell”, and reproduction sequence is controlled. Inparticular, in a recording medium having two information recordinglayers, it is designated that one Cell should not be recorded in pluralrecording layers.

Accordingly, in commercial DVD-Video software, in order to record AVdata in recording medium having two layers by conforming to DVD-Videoformat, the AV data to be recorded in each layer is preliminarily editedand recorded so that one Cell should not be recorded in plural layers(see, for example, patent document 1, non-patent document 1).

By using DVD recorder, however, when recording in real time in arecording medium having two layers, the AV data cannot be recorded byauthoring preliminarily so that one Cell should not be recorded inplural layers, it was impossible to record in conformity with DVD-Videostandard.

-   -   Patent document 1: JP, 2000-48542, A    -   Non-patent document 1: DVD Specifications for Read-Only Disc        Part 3, version 1.0 Aug. 1996

That is, it is impossible to record in real time so as to conform toDVD-Video standard designating “one Cell should not be recorded overplural layers.”

DISCLOSURE OF INVENTION

The invention is devised to solve this problem, and it is hence anobject thereof to present an information recording apparatus and arecording method capable of recording AV data in real time to arecording medium having two information recording layers whilesatisfying the required specification.

A first aspect of the invention provides a recording method forrecording data in basic reproduction unit to a recording medium having afirst recording layer and a second recording layer. The basicreproduction unit may include a plurality of data units havingcontinuity in time, and each data unit may be a minimum unit forrecording and reproducing data to a recording medium. The recordingmethod includes the steps of detecting a size of an unrecorded region ofthe first recording layer, while recording data in reproduction basicunit in the first recording layer, comparing the size of the unrecordedregion of the first recording layer with a specified value, and stoppingrecording into first recording layer at boundary of the basicreproduction unit when the size of the unrecorded region is smaller thanthe specified value, and recording a subsequent data in the secondrecording layer.

A second aspect of the invention presents an information recordingapparatus for recording data in basic reproduction unit in a recordingmedium having a first recording layer and a second recording layer. Theinformation recording apparatus includes an encoder operable to encodedata, a buffer operable to temporarily store the encoded data, a driveoperable to record the encoded data in the first or second recordinglayer of the recording medium, a recording controller operable tocontrol the encoder, buffer and drive, and a detector operable to detectwhether the recording position of the first recording layer reaches anend of the first recording layer while recording data in the basicreproduction unit in the first recording layer. The detector detects asize of an unrecorded region of the first recording layer, and comparesthe size of the unrecorded region of the first recording layer with aspecified value, and determines that the recording position of the firstrecording layer reaches an end of the first recording layer when thesize of the unrecorded region becomes smaller than the specified value.When it is determined that the recording position of the first recordinglayer reaches the end, the controller controls recording so as to stopthe recording in the first recording layer at the boundary of the basicreproduction unit, and record a subsequent data in the second recordinglayer.

According to the invention, data of basic reproduction unit is preventedfrom being recorded in two layers, in a recording medium having tworecording layers. It is hence possible to satisfy the requirementspecified, for example, in DVD-Video standard.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an information recording apparatus inembodiment 1 of the invention.

FIG. 2 is a diagram of AV data conforming to DVD-Video standard.

FIGS. 3A to 3D are explanatory diagrams of changeover method from afirst recording layer to a second recording layer in embodiment 1 of theinvention.

FIG. 4 is a flowchart of recording process for changing over from thefirst recording layer to the second recording layer in embodiment 1 ofthe invention.

FIGS. 5A and 5B are explanatory diagrams of changeover method from thefirst recording layer to the second recording layer in embodiment 2 ofthe invention.

FIGS. 6A to 6C are explanatory diagrams of changeover method from thefirst recording layer to the second recording layer in embodiment 2 ofthe invention.

FIG. 7A is an explanatory diagram of recording of dummy data inembodiment 3 of the invention.

FIG. 7B is a block diagram of information recording apparatus inembodiment 3 of the invention.

FIGS. 8A to 8D are explanatory diagrams of changeover method from thefirst recording layer to the second recording layer in embodiment 4 ofthe invention.

FIGS. 9A to 9C are explanatory diagrams of changeover method from thefirst recording layer to the second recording layer in embodiment 5 ofthe invention.

FIG. 10 is a flowchart of recording process for changing over from thefirst recording layer to the second recording layer in embodiment 5 ofthe invention.

FIG. 11 is an explanatory diagram of division of Cell data in embodiment5 of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the accompanying drawings, preferred embodiments of theinvention are described specifically below.

Embodiment 1 1. Configuration of Information Recording Apparatus

FIG. 1 is a block diagram of information recording apparatus accordingto the invention. An information recording apparatus 10 recordsinformation in a recording medium 20 having two recording layers (firstrecording layer, second recording layer). In this embodiment, as anexample of recording medium 20, a recording medium conforming to DVDstandard is used. The information recording apparatus 10 of theembodiment conforms to DVD-Video standard, and can record one Cell(detail described blow) within on layer only, in real-time recording tothe recording medium 20 having two recording layers.

As shown in FIG. 1, an information recording apparatus 10 includes a DVDdrive 1 for recording and reproducing data to the recording medium (DVD)20 and a hard disk drive 2, as data storing means. The informationrecording apparatus 10 further includes an encoder 4 for encoding andgenerating AV data to be recorded, an encoder controller 5 forcontrolling the encoder 4, a buffer memory 6 for temporarily storing theAV data to be recorded, an end detector 7 for detecting whether arecording position of the recording medium nearly reaches the end of thefirst recording layer and issuing an end detection notice signal, and arecording controller 9 for controlling data recording to the DVD drive1.

The encoder 4 generates data to be recorded to a recording medium 20,and writes the data into the buffer memory 6. The data written in thebuffer memory 6 is sequentially recorded into the recording medium 20 bythe DVD drive 1. While the data is being recorded in the first recordinglayer, the end detector 7 detects a size of unrecorded region of therecording medium 20, and issues the end detection notice signal when thesize becomes smaller than a specified value. On receiving the enddetection notice signal, the recording controller 9 changes over therecording layer from the first recording layer to the second recordinglayer.

An information recording apparatus 10 includes the hard disk drive 2which is a recording medium different from the DVD drive 1. Hence, datacan be dubbed between the DVD drive 1 and hard disk drive 2.

Herein, the Cell is a basic reproduction unit of AV data specified byDVD standard, and is composed of plural VOBUs (Video Object Units) whichare disposed continuously in logical address (that is, having continuityin time). The Cell is defined in the navigation data as basic unit ofreproduction by the control software of the device. A size of Cell canbe set arbitrarily in a range of a specified upper limit (maximum Cellnumber) as far as the SCR (system clock reference) and PTM (presentationtime) are continuous and attributes such as aspect ratio (4:3 or 16:9)are not changed.

In this embodiment, of the two recording layers of the recording medium20, a layer in which data is first recorded is called “first recordinglayer” and next layer to be recorded is called “second recording layer.”The first recording layer is preferably at a side farther from themedium surface to be irradiated with light. Recording is started fromthe first recording layer, and when the vacant capacity of the firstrecording layer become smaller than a specified value, the recordinglayer is changed from the first recording layer to the second recordinglayer. Data is recorded in the first recording layer in a direction frominner circumference to outer circumference of recording medium 20, whilerecorded in the second recording layer in a direction from the outercircumference to the inner circumference. Same effects can be obtainedwhen the recording direction is reverse.

2. Configuration of AV Data

Referring to FIG. 2, configuration of AV data conforming to DVD-Videostandard is explained. In DVD-Video standard, every program has a datastructure called VTS (Video Title Set) 40. VTS 40 is composed of VTSI(41) as AV data control information and menu control information, VTSMVOBS (43) as MPEG2 data for menu, VTSTT_VOBS (45) as MPEG2 data of AVdata, and VTSI_BUP (47) as backup data of VTSI. VTSTT_VOBS is composedof a plurality of units called VOBs (Video Objects) 60 specified inISO/IEC 13818-1. Further, VOB (60) is composed of a plurality of Cells(61) which are units for starting or ending reproduction. The Cell (61)is composed of a plurality of MPEG2 data of about 0.4 to 1.2 secondscalled VOBUs (video object units) (65) as minimum units for recordingand reproduction to the recording medium. According to pages VI 3-5,section 3.1.5 of non-patent document 1, one Cell is required to bepresent wholly in one recording layer.

3. Recording Operation

FIGS. 3A to 3D are explanatory diagrams of data recording method in tworecording layers in this embodiment. In this embodiment, the maximumCell size is compared with unrecorded region size of the first recordinglayer, and when the unrecorded region size becomes smaller than themaximum Cell size, the recording layer is changed to the secondrecording layer.

The maximum Cell size is the upper limit of Cell size, and is determineddepending on the specification of the information recording apparatus10, that is, control of the encoder for generating AV data. In theDVD-Video standard, since the number of Cells per title is limited tothe maximum of 255, when recording one title by using the firstrecording layer and the second recording layer, the maximum Cell size ispreferred to be 34 MB or more. When recording plural titles, the maximumCell size may be controlled to be set larger than the value obtained bydividing the total remaining capacity of the first and second recordinglayers by 255 by the encoder 4, thus to change the value of maximum Cellsize properly.

FIG. 4 is a flowchart of changeover process of recording layers in thisembodiment. A size of unrecorded region of the first recording layer isequal to the entire capacity of the first recording layer whenunrecorded as shown in FIG. 3A. When recording starts, the sizedecreases by the recorded portion as shown in FIG. 3B. The recordingcontroller 9 starts recording from the first recording layer (S11). Theend detector 7 compares unrecorded region size of the first recordinglayer with the maximum Cell size (S12). When the maximum Cell size issmaller than the unrecorded region size of the first recording layer (Noat S13), an end detection notice signal showing “Not detected” isissued. At this time, the recording controller 9 continues to record inthe first recording layer (S14). On the other hand, when the maximumCell size is greater (Yes at S13), the end detector 7 issues an enddetection signal showing “Detected.” At this time, the recordingcontroller 9 stops recording in the first recording layer at the Cellboundary, and changes over the recording layer to the second recordinglayer (S15) (see FIG. 3C), and thereafter AV data is recorded in thesecond recording layer (S16) (see FIG. 3D).

Thus, in the recording method according to this embodiment, one Cell isnot recorded in two layers.

Embodiment 2

This embodiment relates to other method of changeover from firstrecording layer to second recording layer. The configuration of theinformation recording apparatus is same as in embodiment 1.

According to DVD-Video standard cited in non-patent document 1,information called “Navigation pack” which includes reproduction controlinformation and search information for AV data compiled on the basis ofAV data (MPEG data) 51 in Cell must be attached to the beginning of Celldata.

Therefore, generally, when recording in real time in a recording medium20, as shown in FIG. 5B, Cell data 61 including Navigation pack 53 isonce compiled on a buffer memory 6, and then recorded in the recordingmedium 20. At this time, the actual data size D of Cell data 61 compiledon the buffer memory 6 is established. The data size D Is used as thebasic data unit in actual reproduction. In this embodiment, whenrecording in the first recording layer, the actual Cell data size Dcompiled on the buffer memory 6 is compared with unrecorded region sizeof the first recording layer, and when the unrecorded region sizebecomes smaller than the Cell data size D, it is judged that therecording position in the first recording layer has reached the end, andthe recording layer is changed from the first recording layer to thesecond recording layer.

More specifically, as shown in FIG. 6A, recording starts from the firstrecording layer. While recording in the first recording layer, theactual data length of Cell data compiled on the buffer memory 6 iscompared with the unrecorded region size of first recording layer. Asshown in FIG. 6B, when the actual data length of Cell data 61 is longer,recording in the first recording layer is stopped at the Cell boundary,and the recording layer is changed to the second recording layer, andthe AV data after the Cell data compiled on the buffer memory 6 isrecorded in the second recording layer (see FIG. 6C).

Embodiment 3

In embodiment 1 or embodiment 2, the recording in the second recordinglayer starts while the unrecorded region is left over in the firstrecording layer (see FIG. 3D). In a general DVD player, if recorded inone layer only-out of two recording layers, there may be a case thatdata can not be read out due to characteristics of the drive.Accordingly, if unrecorded region is left over in the first recordinglayer, a problem occurs in compatibility of the recording media.According to the DVD-Video standard, moreover, presence of discontinuouslogical address is not permitted in stream data in the same title.

To solve these problems, in this embodiment, dummy data is recorded inwhole unrecorded region of the first recording layer at either of thefollowing timings after transfer to recording in the second recordinglayer as shown in FIG. 7A to eliminate unrecorded state:

(1) After recording in the first recording layer, before startingrecording in the second recording layer; and

(2) When finalizing the recording medium.

In this case, the dummy data is stream data composed of one Cell, ofwhich size is same as the unrecorded region size of the first recordinglayer. Since the timing is fixed, (1) is better than (2).

The dummy data is composed as follows. That is, at least the beginningVOBU of Cell includes video data, and the remaining VOBUs are composedof padding packets. The padding packet has a data structure specified inISO/TEC 13818-1 Table 2-17 as the standard of MPEG2, the packet startcode is 0x000001BE, and data 0xFF is recorded in all data regions.

FIG. 7B shows a configuration of information recording apparatus of theembodiment capable of writing dummy Cell. The information recordingapparatus 10 b of this embodiment further includes a dummy Cellgenerator 8 for receiving the end detection notice signal and generatingthe dummy Cell data, in addition to the configuration shown inembodiment 1. The dummy Cell generator 8 can receive the end detectionnotice signal from the end detector 7. When receiving the end detectionsignal, the dummy Cell generator 8 generates the dummy Cell data, writesit to the buffer memory 6, and notifies the recording controller 9 ofthe generation of the dummy data. When receiving the dummy datageneration notice, the recording controller 9 stops recording of AVdata, and starts recording of dummy Cell data. When recording of dummyCell data is over, recording of AV data is resumed. The layers arechanged over, while recording the dummy Cell data or after finishingrecording. Other process is same as in embodiments 1 and 2.

Embodiment 4

This embodiment relates to a recording method of starting recording ofthe second recording layer from a radius position on the secondrecording layer corresponding to a radius position of recording end ofthe first recording layer.

FIGS. 8A to 8D show the recording method from the first recording layerto the second recording layer in the embodiment. In the foregoingembodiments, recording of the second recording layer is started from theoutside end position of the second recording layer (see FIG. 3D, FIG.6C). By contrast, in this embodiment, as shown in FIG. 8D, recording ofthe second recording layer is not started from the beginning of therecording region, but started from a radius position on the secondrecording layer corresponding to the radius position of recording endposition on the first recording layer. The advantage of this recordingmethod is that the seek time from the first recording layer to thesecond recording layer is shorter because the end of stream data infirst recording layer and the beginning of stream data in secondrecording layer are in the relation of upper and lower layers physicallyat the same radius position. At this time, a region R2 from thebeginning of the second recording layer to recording start point of thesecond recording layer is unrecorded region (unrecorded region of thesecond recording layer), but it is processed by dummy data recording asfollows.

According to specification in pages VI 3-5, section 3.1.5 of non-patentdocument 1, one Cell should not be recorded over plural layers. Thusthis embodiment generates first dummy data composed of one Cell of whichsize is equal to the size of unrecorded region R1 of the first recordinglayer, and second dummy data composed of one Cell of which size is equalto the size of the unrecorded region R2 of the second recording layer.The first and second dummy data are recorded in unrecorded regions R1and R2 after finishing recording of the first recording layer and beforestarting recording of the second recording layer, or when finalizing.

Since the first dummy data and second dummy data are composed of a Cell,respectively, information about beginning address and terminatingaddress of Cell is included in the video title set address tableinformation (VTS_C_ADTI) in VTS IFO which is specified in pages VI 4-77of non-patent document 1.

Embodiment 5

In this embodiment, when changing over the recording layer from thefirst recording layer to the second recording layer, the Cell to berecorded is divided, and recorded in each layer. The informationrecording apparatus has the same configuration of that shown in FIG. 7B.

Suppose usage of dubbing AV data existing in a device such as hard diskdrive 2 into recording medium 20. In this case, since the AV data isalready present in the hard disk drive 2, the time restriction is not sosevere as in real-time recording. Hence the following control ispossible near the end of firs layer in order to satisfy the DVD-Videostandard that one Cell should not be recorded over plural layers.

As shown in FIG. 9A, recording is started from the first recordinglayer, and when the size of unrecorded region of the first recordinglayer becomes smaller than the size of Cell data 61 near the end of thefirst recording layer as shown in FIG. 9B, in order to satisfy theDVD-Video standard that one Cell should not be recorded in plurallayers, the original Cell (61) is divided to generate a first divisionCell (61 a) and a second division Cell (61 b) as shown in FIG. 9C. Thesedivision Cells (61 a, 61 b) are recorded in the first recording layerand the second recording layer, respectively. In this embodiment, too,dummy data is recorded in regions R1 and R2.

FIG. 10 is a flowchart of recording method by the information recordingapparatus according to this embodiment.

The recording controller 9 judges whether the recording position of thefirst recording layer reaches the end in the method described in theforegoing embodiments while recording in first recording layer (S21),and judges affirmatively (S22), the original Cell (61) is divided intothe first division Cell (61 a) and the second division Cell (61 b)(S23). The first division Cell (61 a) is recorded in the first recordinglayer (S24), the recording layer is changed to the second recordinglayer (S25), and the second division Cell (61 b) is recorded in thesecond recording layer, and thereafter data is recorded in the secondrecording layer (S26).

Referring to FIG. 11, a method of generating the division Cell is morespecifically described. The original VOBU group 51 including pluralVOBUs is divided in units of VOBUs. At the beginning of first dividedVOBU group 51 a and second divided VOBU group 51 b, Navigation packs 53a and 53 b are attached, respectively. The information of Navigationpacks 53 a and 53 b includes reproduction control information and searchinformation according to non-patent document 1. The reproduction controlinformation specifies reproduction start time and reproduction end timeof the VOBU group. The search information specifies an address of eachVOBU in VOBU group.

Therefore, Navigation pack 53 a is newly added to the beginning of thesecond VOBU group 51 b obtained by dividing the Cell 61 to generate thesecond division Cell (61 b). In the first VOBU group 51 a in whichNavigation pack 53 has been already added to the beginning, theNavigation pack 53 is revised to Navigation pack 53 a according to thefirst VOBU group 51 a to generate the first division Cell (61 a). Thegenerated first division Cell (61 a) is recorded in the first recordinglayer, the recording layer to be used is changed over to the secondrecording layer, and the second division Cell (61 b) is recorded in thesecond recording layer.

Thus, according to these embodiments, when recording in the firstrecording layer, the unrecorded region size of the first recording layeris compared with a specified Cell unit size to judge if a vacant regionis sufficient or not. If the vacant region is not sufficient, recordingin the first recording layer is stopped, and recording in the secondrecording layer is started. Hence, one Cell is not recorded in plurallayers, and it is possible to record by satisfying the requirements ofDVD-Video standard. Especially, according to this embodiment, ascompared with embodiments 1 and 2, the efficiency of using the recordingregion is further enhanced.

In the embodiments, the recording method conforming to DVD standard isexplained. However, the concept of the invention is not limited theapplication conforming to DVD standard only, but may be applied to otherconditions of use in which recording of specified data unit over twolayers is prohibited or not recommended.

The concepts of the respective embodiments may be properly combined sofar as not contrary to each other in structure or action.

The invention is described herein in relation to specific embodiments,but the invention may be changed and modified in several forms, easilyfor those skilled in the art, without departing from the spirit of theessential characteristics thereof. Hence the invention is not limited tothe present embodiments alone, but is defined by the appended claimsthereof. This application is based upon and claims the benefit ofpriority from the prior Japanese Patent Application No. 2004-214037,filed on Jul. 22, 2004, the entire contents of which are incorporatedherein by reference.

INDUSTRIAL APPLICABILITY

The invention can be applied in recording technology into recordingmedium (for example, DVD-R (Digital Versatile Disk-Recordable)) havingtwo layers for recording information in the case it is required thatdata in specified data management unit should be recorded in one layeronly. The invention is useful for an information recording apparatusconforming to, for example, DVD-Video standard.

1. A recording method for recording data in basic reproduction unit to arecording medium having a first recording layer and a second recordinglayer, the method comprising the steps of: detecting a size of anunrecorded region of the first recording layer, while recording data inthe basic reproduction unit in the first recording layer; comparing thesize of the unrecorded region of the first recording layer with aspecified value; and stopping recording in the first recording layer atthe boundary of the basic reproduction unit when the size of theunrecorded region is smaller than the specified value, and recording asubsequent data in the second recording layer.
 2. The recording methodaccording to claim 1, wherein the specified value is a maximum allowablesize of the reproduction basic unit.
 3. The recording method accordingto claim 1, wherein the specified value is a size of data being about tobe recorded in the first recording layer.
 4. The recording methodaccording to claim 1, wherein dummy data is recorded in the unrecordedregion of the first recording layer after stopping recording in thefirst recording layer and before starting recording in the secondrecording layer.
 5. The recording method according to claim 1, wherein adummy data is recorded in the unrecorded region of the first recordinglayer when finalizing after stopping recording in the first recordinglayer.
 6. The recording method according to claim 1, wherein a radiusposition of recording start position on the second recording layercorresponds to a radius position of recording end position on the firstrecording layer.
 7. The recording method according to claim 1, wherein adata to be recorded in the first recording layer is divided into firstand second data units when a size of the unrecorded region becomessmaller than the specified value, and the divided first data unit isrecorded in the first recording layer and the divided second data unitis recorded in the second recording layer.
 8. An information recordingapparatus for recording data in basic reproduction unit to a recordingmedium having a first recording layer and a second recording layer, theapparatus comprising: an encoder operable to encode data; a bufferoperable to temporarily store the encoded data; a drive operable torecord the encoded data in the first or second recording layer of therecording medium; a recording controller operable to control theencoder, the buffer and the drive; and a detector operable to detectwhether the recording position of the first recording layer reaches anend of the first recording layer while recording data in basicreproduction unit in the first recording layer, wherein the detectordetects a size of an unrecorded region of the first recording layer, andcompares the size of the unrecorded region of the first recording layerwith a specified value, and determines that the recording position ofthe first recording layer reaches the end when the size of theunrecorded region becomes smaller than the specified value, and therecording controller, when it is determined that the recording positionof the first recording layer reaches the end, controls the recording soas to stop the recording in the first recording layer at the boundary ofthe basic reproduction unit, and record a subsequent data in the secondrecording layer.
 9. The information recording apparatus according toclaim 8, wherein the specified value is a maximum allowable size of thereproduction basic unit.
 10. The information recording apparatusaccording to claim 8, wherein the specified value is a size of databeing about to be recorded in the first recording layer.
 11. Theinformation recording apparatus according to claim 8, wherein therecording controller records a dummy data in the unrecorded region ofthe first recording layer after stopping recording in the firstrecording layer and before starting recording in the second recordinglayer.
 12. The information recording apparatus according to claim 8,wherein the recording controller records a dummy data in the unrecordedregion of the first recording layer when finalizing after stoppingrecording in the first recording layer.
 13. The information recordingapparatus according to claim 8, wherein a radius position of a recordingstart position on the second recording layer corresponds to a radiusposition of a recording end position on the first recording layer. 14.The information recording apparatus according to claim 8, wherein, whenit is detected that the recording position of the first recording layerreaches the end, the recording controller controls the recording so asto divide the data to be recorded in the first recording layer into thefirst and the second data units, and record the divided first data unitin the first recording layer and record the divided second data unit inthe second recording layer.
 15. The information recording apparatusaccording to claim 8, further comprising a hard disk drive for storingdata.